1. Field of the Invention
The present invention relates to an air conditioning blow-out port device mounted in an instrument panel or the like in a vehicle, and a process for producing the same by a two-stage injection molding.
2. Description of the Prior Art
There is such a conventionally known air conditioning blow-out port device which includes a housing having a plurality of pairs of shaft holes provided in a coaxial arrangement in opposed wall portions of a peripheral wall thereof to extend through the opposed wall portions, and a plurality of blades each having a pair of support shafts which are projectingly provided coaxially on opposite end faces of a blade body and rotatably fitted into the shaft holes, each of tip ends of the support shaft projecting from an outer surface of each of the opposed wall portions. The reason why the tip end of each support shaft projects from the outer surface of corresponding one of the opposed wall portions is that the support shaft is formed long enough to reliably prevent the disengagement of the blade from the housing.
In this case, in order to smoothly rotate the blades, it is necessary to reduce the rotational resistance of each blade with respect to the housing to the utmost.
The above-described air conditioning blow-out port device is produced using a synthetic resin by a two-stage injection molding process which includes a primary injection step of molding a housing and a secondary injection step of molding blades by forming support shaft molding cavities by shaft holes in the housing and blind holes located in slide dies to communicate with the shaft holes.
However, the prior art process has a problem in that mating faces of the slide dies and the housing are located in the support shaft molding cavities in proximity to bottom surfaces of the blind holes and for this reason, a pressure in the blind hole at a side of its bottom surface becomes high and hence, a molten synthetic resin is squeezed out into a gap between the mating faces, and as a result, flashes are formed on an outer peripheral surface of each support shaft which causes the rotation of the blade to be defective in smoothness.